The answer to how serious the Islanders are about winning now came around dinner time on Sunday night, when general manager Garth Snow acquired high-scoring forward Thomas Vanek from the Sabres in exchange for Matt Moulson, a first-round pick in 2014 and a second-round pick in 2015.

If the price seems rather high for most, Snow saw it as opportunity to not let the momentum of his franchise die on the vine after last season’s breakthrough run to the postseason.

“As an organization, we are not satisfied with what our record is and where we are as a team,” Snow told The Post Sunday night, his team sitting at 4-4-3, tied for second in the Metropolitan Division, as the Isles prepare for Tuesday night’s battle with the Rangers at the Coliseum.

“We expected a little bit better,” Snow said. “We had an opportunity to acquire an elite winger, so we did it. Matt Moulson has been a great player for us the last couple years. Sometimes you have to give up something to get something.”

Both Moulson and Vanek are unrestricted free agents at the end of this season, and Snow said negotiations with Vanek on an extension have not started and were not part of making this trade.

“We traded a player who was going to be a free agent for a player who is going to be a free agent,” Snow said. “We’re looking to make our team better, that’s the bottom line.”

Vanek, 29, has played with the Sabres since 2005, and has twice reached the 40-goal mark. He is working on the final season of a seven-year deal that carried an annual salary-cap hit just more than $7.1 million, and will be joining fellow Austrian Michael Grabner — whose role has suddenly changed into part-time salesman for Long Island.

“He’s got a ton of upside,” Snow said of Vanek. “He’s a responsible player. He’s powerful, he skates. He’s a high character hockey player and person. We’re excited to have him it here.”

It wasn’t an easy deal for Snow, as Moulson was one of the best pickups of his tenure in the front office. After being drafted by the Penguins in 2003, then getting his only NHL action in part-time with the Kings for two seasons, Moulson came to the Islanders on a minor-league tryout in 2009, and ended up signing a three-year, $9.4 million deal the following season.

He scored 30-plus goals for the team for three straight years from 2009-2011, then notched 15 goals last season in the lockout-shortened 48-game schedule. He did almost all of it alongside superstar center John Tavares, who was the first-overall pick the year Moulson came to the team.

Moulson will turn 30 on Friday, and he and his wife had their second child on Oct. 11.

Yet this deal was not Moulson for Vanek, but included two draft picks Buffalo general manager Darcy Regier regarded as paramount, his team quickly becoming a laughingstock with a league-worst 2-10-1 record and its bullish ways.

But for Snow, this was a declaration that after six seasons without reaching the playoffs, last season’s first-round loss to the Penguins was not a one-time deal. His franchise hasn’t won a playoff series since 1993, and he has enough confidence in what he has built — from the top of the organization to the bottom — this trade made sense for him now and into the future.

“It makes giving up draft picks of that nature a little less of a burden when you’ve had the drafts that we had and the prospect pool we have,” Snow said. “Yes, it’s a high price to pay, but you have to give something to get something.”